Numerical Simulation And Investigation On Performance Of Ejector

China, as world’s biggest energy consumer, faces the urgent task of advanced energy technologies. The principle of steam ejector heat pump is the same as steam ejector refrigerator. They can use low grade heat source and improve energy utilization, and ejectors are their important part. Ejectors do not contain any moving parts, they are simple and highly reliable devices with low capital and maintenance costs. Most ejectors use wide range of compressed air as the motive fluid. However, ejectors have a low efficiency. In this study, ejector was simulated by Fluent. The major consideration of this study is to optimize ejector efficiency. Consequently, the operating cost is minimized.The conclusions are educed as follows:(1) According to gas dynamics, an ejector from a paper mill of Guangxi was design. One-dimensional can not display the inner flow field of ejector. The study uses the flexibility of Fluent, simulates the inner flow field. Working parameters and geometric parameters are analyzed to find out the factors which restrict the performance of ejector.(2) The lobed nozzle has a good and wide applicable prospect, they are highly reliable devices with low capital, little change in the structure and easy to replace, and they can applied to miniaturization of ejectors. As an example, the study simulate an enhance ejector in a heat pump, the results from Fluent indicates that the ejector efficiency improves significantly. Flow phenomenon is analyzed in ejector with the lobed nozzle, the principle of the lobed nozzle was discussed.(3) Refrigerants can restrict the performance of ejector, except working parameters and geometric parameters. This paper presents a CFD model to predict the working of refrigerants in an ejector refrigeration system, the simulation results indicate that this model is reasonable and the errors between the experimental and predicted values are within5%. The performances of ejector refrigeration system adopted three environmentally friendly refrigerants with similar normal boiling points, R245ca, R245fa and R236ea were compared. The results indicate that R245ca, R245fa and R236ea can be appropriate candidate of R123.